Catamenial device



0d. 24, 1961 G, c, GRAHAM, JR 3,005,456

CATAMENIL DEVICE Filed July 3. 1956 ATTO RN EY `Hersey Filed July 3, 1956, Ser. No. 595,716

13 Claims. (Cl. 12S-28S) The present invention relates to cata-menial devices of improved absorbency and to methods of making the Sme. More specifically, the present invention is concerned with catamenial napkins and tampons having greater fluid absorptive capacities than are possessed by presently-use cellulosic catamenial devices.

Catamenial devices presently in use depend primarily for their efficiency upon the capacity of their brous absorptive pad portions to receive, absorb and retain menstrual fluids. These fibrous pad portions are normally made of cellulosic materials, notably wood pulp, paper, cotton, rayon, or blends and mixtures thereof, which possess excellent absorptive characteristics and properties. Notwithstanding such characteristics and properties, however, the efforts to increase the absorptive capacities of such materials are many and varied.

For example, larger and bulkier tampons and napkins have been manufactured and possess -greater absorptive capacities but are not fully acceptable inasmuch as the increased size and volume have caused irritation and discomfort, particularly in the case of catamenial tampons. Other efforts have been directed to the use of more highly compressed catamenial devices by using greater pressures on the fibrous materials during the processing and manufacturing of these sanitary devices whereby Agreater masses of Ifibers can be contained within normal or regular sizes and theoretically absorb and hold more fluid. Such efforts, however, have similarly not met with complete success. All in all, a great deal of effort has been expended toward the development of improved absorbent bodies but there still remains considerable room for irnprovement.

It is therefore a principal object of the present invention to provide a catamenial device of improved absorbency without necessarily requiring greater amounts of absorbent fibrous materials or the use of greater pressures during the manufacturing of such devices.

It has been found that the use of a modified cellulosic product, namely a carboxylal'kyl cellulose salt, such as sodium carboxymethyl cellulose or sodium carboxyethyl cellulose, in such catamenial devices creates enhanced fluid absorptive capacities therein, provided the average degree of substitution of the carboxyalkyl radical in the cellulose molecule is maintained within controlled limits and is not permitted to exceed specified values to be described more fully hereinafter.

in the accompanying drawings and following specification, there are illustrated and described preferred designs of articles of manufacture embodying the present invention, but it is to be understood that the inventive concept is not to be considered limited to the constructions disclosed except as determined by the scope of the appended claims.

Referring to the accompanying drawing:

FIG. l is a cross-sectional view of a sanitary napkin, containing the improved absorbent Ipad of the present invention;

FIG. 2 is a cut-away view in elevation of a catamenial tampon containing an improved absorbent pad of the present invention; and

FIG. 3 is a graph showing the fiuid absorptive capacities of a carboxymethyl cellulose tampon of the present invention.

Patented Oct. 24, 1961 In the embodiments of the invention shown in the drawing, a sanitary napkin 1 comprises an upper fibrous absorptive pad 2 and a lower fibrous absorptive pad 3 (both preferably of fluffed wood pulp) which are separated by a water repellent tissue layer 4. Both pads 2, 3 and the layer 4 are lfolded within an envelope 5 made of paper or similar material, which, in turn, is wrapped within an external textile cover 6 of a nonwoven material or of a woven material such as gauze. The textile'cover 6 has a :length greater than the other elements above-recited and extends beyond the ends thereof to form fastening or pinning tabs (not shown) to position the napkin in place to conform to the body contours of the user and to receive, absorb and retain catamenial fluids. This structure is exemplary of a form of sanitary napkin in commercial use and is employed to illustrate the invention. It should be realized, however, that such is not to be construed as limitative of the broader aspects of the .present invention.

In FIG. 2, there is illustrated a catamenial device C10 comprising a hollow cylindrically-shaped container or applicator 11 and a smaller plunger or ejector 12, slidably -positioned within the applicator 11. A fibrous absorptive pad 13 (preferably of cotton or cotton and other cellulosic materials) is positioned within the applicator 11 and is adapted to be slidingly ejectible therefrom by movement of the plunger 12 intoy the applicator 11 so as to be positioned in a body cavity to conform to the body contours of the user and to receive, absorb and retain catamenial fluids. A withdrawal string or cord L14 is secured preferably to the base of the tampon and is of sufficient length that thev free end thereof extends outward-ly o-f the body cavity for withdrawal of the tarnpon after use. This structure, similarly, is exemplary of a form of catamenial tampon in commercial use and is employed primarily to illustrate the invention. It should be realized, however, that such is not limitative but merely illustrative of the invention.

The rfibrous absorptive pad portions 2 and 3 of the sanitary napkin 1 are normally manufactured from a fiuffed cellulosic wood pulp product wherein the average lengths of the cellulosic fibers are relatively short, usually less than 1% inch, and are not capable of being processed by standard ltextile equipment, such as a card. On the other hand, the fibrous absorptive pad portion 13 of the tampon 1G comprises absorbent cellulosic fibers having an average fiber length of at least about J/g inch and up to about 21/2 inches or longer and are capable of being processed by standard textile equipment (such as a card) into the desired forms and shapes.

1 The cellulosic fibers of these fibrous absorptive pad portions are modified according to the present inventive concept within pre-determined limits whereby their fluid absorptive capacities are considerably enhanced. More explicitly, a speci-fied percentage or proportion of the hydroxyl radica-ls of the cellulose molecule are modified by etherification or carboxyalkylation processes whereby there is obtained a carboxyalkyl cellulosic product having a calculated degree of carboxylalkyl substitution. These products are exemplified by sodium carboxymethyl cellulose and sodium carboxyethy-l cellulose.

In the specification terminology, the term carboxymethyl cellulose (or cellulose glycolic acid ether) refers to the salts thereof, particularly the sodium salt.

4 Similarly, carboxyethyl cellulose (or cellulose hydroxypropionic acid ether) refers to its salts, particularly the sodium salt.

The salt of cellulose glycolic acid ether (salt of carboxymethyl cellulose), which may be used to prepare the catamenial devices of the invention may be described structurally as:

where x is at least equal to 0.03 but not greater than 0.35 and y is a large whole number. The ring structure represents the anhydroglucose residue which is linked in known. manner to similar residues on either side to form a long chain cellulose structure. The bracketed H atoms are attached to side-chain oxygen atoms in the anhydroglucose residue in known fashion. Similarly, the bracketed --(CH2-COONa) groups are attached to the residue through side-chain oxygen linkages by substituting for the aforementioned H atoms. The salt of carboxyethyl cellulose (salt of cellulose hyd-roxypropionic acid ether), which is an alternate to the salt of carboxymethyl cellulose, may be described structurally as:

x, again, being at least equal to 0.03 but not greater than 0.35 and y a large whole number. The C2H4 ygroup is preferably -CH2-CH2.

The general formula of the materials used to prepare catamenial devices according to the invention is therefore:

where x is at least equal to 0.03 but not greater than 0.35, n is 1 or 2, and y is a large whole number.

The degree of substitution (D.S.), a term commonly employed in connection with cellulose derivatives of the nature used in the invention catamenial devices, is an important property and indicates the average number of substituent groups per glucose unit `in the cellulose molecular chain (i.e., the value of x in the above formulae). Since there are originally three hydroxyl groups and hence three possible points of substitution per glucose unit, the maximum degree of substitution is 3. It has been found according to the present invention that the degree of substitution is an important factor in determining the absorptive activity of the particular cellulose ether. More specically, it has been found that, as the 'degree of substitution increases, the catamenial absorptive capacity also increases up to a maximum but then rapidly falls thereafter oi to very low values.

Without being bound to the yfollowing theory, it is believed that the increased absorbency is due to the reception and retention of fluids within the individual modi'ed cellulosic fibers in addition to the usual reception and retentionof fluids in the capillary spaces between the individual bers. This phenomenon apparently exists up to a degree of substitution of about 0.35 (approximately one carboxyalkyl radical for every three glucose residues) and surprisingly falls oi and disap- Table 1 Degree of substitution (CMC) Fluid absorbed tampon wt.

It is quite apparent from the graph that values as low as about 0.03 carboxymethyl substitution show improved results but that values in excess of about 0.35 carboxymethyl substitution markedly decrease the absorptive properties of the materials and consequently render the same undesirable for use in catamenial devices. The tampons used in deriving the values of the above table are the so-called Super size, weighing approximately 54 grains (3.5 grams) and having a length of about 1% inches and a diameter just under 0.6 inch.

The test procedures used in obtaining the values shown in Table 1 are as follows:

The test tampons (dry) comp-rising carboxymethyl cellu-losic fibers having an average liber length greater than 1/2 inch are measured for length, diameter and weight and are then placed in porous plate Buchner funnels. A resilient rubber surface which snugly iits within the iunnel is lowered to contact the tampon and pressure equal to about 24 inches of water is applied to the tampon through the resilient rubber surface. The test uid (sp. gr. 1.04) is introduced upwardly through the stem of the funnel and just covers the test tampon. Absorption is permitted to take place at the 24 inch water pressure for 5 minutes. The test fluid is then removed and the test tampon is permitted to drain for l minute under the 24 inch water pressure. The pressure is then removed and the wet tampon is removed, quickly weighed and the results recorded. Test samples of similar length, diameter and weight tampons of untreated cotton fibers (0% CMC) are tested along -with the 5 and 10% carboxymethyl cellulose test tampons and `give comparative results of 2.8 and 2.8, as compared to the 3.12 and 4.26 values obtained for the treated test tampons as noted in the table.

The particular process used to introduce the carboxyalkyl radical into the glucose residue in the cellulose may be selected from any of the known processes now used commercially involving the use of cellulose (preferably cotton or iluffed wood pulp in the desired fiber length form), monochloracetic acid and sodium hydroxide. In the case of the iluled wood pulp, the only requisite is the introduction of the pre-'determined number of carboxymethyl radicals in the `glucose residues. In the case of the cotton bers, however, an additional requirement in the selection of the particular process is the control and ability to introduce up to about 0.35 carboxyalkyl groups per glucose residues in the cellulose without destroying the ibrous structure of the cellulosic materials or reducing the liber length to less than about 1/2 inch. The products of such processes are available commercially.

It is to be appreciated that, Since there is an overall average of less than one carboxyalkyl group per glucose residue, some residues will be unaffected and have no carboxyalkyl groups, whereas others may have one, two or perhaps even three carboxyalkyl groups.

Additionally, it is not necessary that all of the iibers be exposed to carboxyalkylating treatment inasmuch as it is possible to carboxyalkylate some of the bers to higher degrees and then mix, blend, or for-m layers of the modified fibers with unmodified fibers whereby the necessary over-all average of below about 0.35 substitution is obtained. Blends of fr-90% cotton and 90- modied cotton are found particularly advantageous.

Alternatively, it is possible to carb'oxyalkylate some of the fibers as high as 0.35 or even to higher degrees and use such fibers in a body as one of the components of an absorptive pad portion, the other components being, for example, lesser modified cellulosic fibers, unmodified cellulosic fibers or other cellulosic materials. In such a case although the degree of carboxyalkyl substitution of the fibers in one `component may thus be very high, the over-all average degree of substitution of the complete absorptive pad portion, when you consider all cellulosic components thereof, may be very low and on the order of 0.22, 0.01 or even lower.

As an example of the blending of unmodified cotton and modified cotton, a 50-50 blend (by weight) of 0.32 D.S. carboxymethyl cellulose and unmodified cotton is employed to make a Super tampon having physical dimensions as described previously. Such a tampon, when evaluated by the test procedures disclosed herein, possesses a ratio of fluid absorbed to tampon weight of 4.53.

Additional 50-50 blends (by weight) of 0.30 D.S. carboxymethyl cellulose and unmodified cotton, when manufactured into test tampons and evaluated by the test procedures described herein, yield ratios of fluid absorbed to tampon weights of 4.46, 4.69 and 5.05, for samples having densities of 170, 100 and 85 grains per cubic inch respectively. Similar samples of 100% unmodified cotton manufactured to similar specifications yield ratios of fluid absorbed to tampon weight of 2.6, 3.4 and 3.8, respectively.

Although the present invention has been described primaiily with carboxymethyl cellulose, it is to be appreciated that carboxyethyl cellulose, such as obtainable from the treatment of the cellulose fibers with sodium hydroxide and rnonochlorpropionic acid, instead of monochloracetic acid, is also applicable within the more general aspects of the present invention.

If desired, the modified cellulosic fibers, either by themselves or in blends or layers with unmodified cellulosic fibers, may be mixed with other fibers to obtain special characteristics and properties. Such other fibers include rayon (regenerated cellulose), cellulose esters (cellulose acetate), vinyl fibers (Vinyon), acrylic fibers ('Orlon, Acrilan), vinyl-acrylic fibers (Dynel), nylon, saran and Daeron polyester fibers. It is to be noted that such fibers, if they are to be used in sanitary napkins in conjunction with flufled wood pulp, may be very short. `On the other hand, if such fibers are to be used in tampons in conjunction with cotton staple of greater length, they should have an average length of at least about 1/2 inch so that they will be capable of being processed on standard textile apparatus and equipment.

While I have shown and described what I believe to be a preferred embodiment of the invention in the matter of simplicity of construction, ease of untilization, etc., it will be appreciated that the details of such construction may be more or less modified within the scope of the claims without departure from the principles of construction or material sacrifice of the advantages of the preferred design.

I claim:

l. A catamenial device of improved fluid absorbency comprising a self-supporting, disposable body of absorbent cellulosic fibers having an average degree of sodium carboxyalkyl substitution of not more than about 0.35 carboxyalkyl radicals per glucose residue in the cellulose, said substituted cellulosic fibers being substantially insoluble in water; and means to position said body of fibers for the reception, absorption and retention of catamenial fluids.

2. A catamenial device as defined in claim 1 wherein the carboxyalkyl radical is carboxyrnethyl.

3. A catamenial device as dened in claim 1 wherein the carboxyalkyl radical is carboxyethyl.

4. A catamenial device as defined in claim 1 wherein the cellulosic fibers are cotton.

5. A catamenial device as defined in claim 1 wherein the cellulosic fibers are flufled wood pulp.

6. A catamenial device of improved fluid absorbency comprising a self-supporting, disposable body of absorbent cellulosic fibers having an average degree of carboxyalkyl substitution of from about 0.03 to about 0.35 carboxyalkyl radicals per glucose residue in the cellulose; and means to position said body of fibers for the reception, absorption and retention of catamenial fluids.

7. A catamenial device of improved fluid absorbency comprising a self-supporting, disposable body of absorbent cellulosic fibers having an average fiber length of about 1/2 inch to about 21/2 inches, said cellulosic fibers having an average degree of sodium carboxyalkyl substitution of from about 0.03 to about 0.35 carboxyalkyl radicals per glucose residue in the cellulose; and means to position said body of fibers for said reception, absorption and retention of catamenial fluids.

8. IA catamenial device of improved fluid absorbency comprising a self-supporting, disposable, substantially cylindrical body of absorbent cellulosic fibers having an average fiber length of at least about 1/2 inch, said cellulosic fibers having yan -average degree of sodium carboxyalkyl substitution of from about 0.03 to about 0.35 carboxyalkyl radicals per glucose residue in the cellulose; an applicator for containing said cylindrical body of cellulosic fibers; and a plunger to eject said cylindrical body of fibers from said applicator and position the same in a body cavity for use therein as a tampon.

9. A catamenial device of improved fluid absorbency comprising a self-supporting, disposable, substantially cylindrical body of absorbent cellulosic fibers having an average fiber length of from about 1/2 inch to about 21/2 inches, said cellulosic fibers having an average degree of substitution of from about 0.03 to about 0.35 sodium carboxyalkyl radicals per glucose residue in the cellulose; an applicator for containing said cylindrical body of cellulosic fibers; and a plunger to eject said cylindrical body of fibers from said applicator and position the same in a body cavity for use therein as a tampon.

l0. A catamenial tampon comprising an elongated mass of cellulosic absorbent material adapted to be car- :ried in the vagina of a Woman during periods of menstrual discharge and means attached to said mass of 'cellulosis absorbent material :for removing said mass from the va-gina, said cellulosis absorbent material containing as an essential ingredient (sodium) carboxykmethylcellulose which is fibrous in nature, having an average degree of carboxyalkyl substitution of from about 0.05 to 0.3 carboxyalkyl radicals per glucose residue in the cellulosic material.

Il. A catamenial tampon comprising an elongated mass of absorbent material adapted to be carried in the vagina of a woman during periods of menstrual discharge and means attached to said mass of absorbent material for removing said mass from the Vagina, said absorbent material ycontaining as an essential ingredient sodium carboxyrnethylcellulose which is brous in nature and substantially insoluble in water.

12. A catamenial tampon comprising an elongated mass of absorbent material adapted to be carried Iin the vagina of a woman during periods of menstrual discharge and means attached to said mass of absorbent material for removing said mass from the vagina, said absorbent material consisting essentially of sodium carboxymethyl- 7 3 cellulose which is fibrous in nature and substantially in- 2,024,218 Haas Dec. 17, 1935 Soluble in Water. 2,486,805 Seymour et al. Nov. 1, 1949 13. A catamenial tampon comprising an elongated mass 2,626,214 Osborne I an. 20, 1953 of absorbent material adapted to be carried in the 2,773,000 Masci et al. Dec. 4, 1956 vagina of a woman during periods of menstrual dis- 5 charge and means attached to said mass of absorbent OTHER REFERENCE? material for removing said mass from the vagina, said The Chemlcal an@ Physlcal PfOPeftleS 0f carboxy' absorbent material `consisting primarily of a mixture of methylceu'ulose and lts Salts; by Brown and H'Ollghton substantially, water-insoluble fibrous sodium carboxyfmmpages 254T258 0f October 1941 so@ Chemical In' methylcellulose and long-bered cotton. 10 dusmal Journal V01' 59 603 26023 1' l Hollabaugh et al.: Industrial and Engmeering Chem- References Cited in the me of this patent istry, Vol. 37, No. l0, October 1945, pages 943-7. (Copy D... 63 l 20 3 UNITED STATES PATENTS m msm Cass 6 2 l) 1,736,714 Lilienfeid Nov. 19, 1929 15 Patent No.. 3 ,005,456

UNITED STATES PATENT. OFFICE CERTIFICATE 0F CORRECTION October 24, 1Q@ George Cooley Graham, Jr.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below. Y

Column 5, line 17, for "0:22" for "untilization" read 0.02 line 6lo for "cellulosis" read utilization --3 column 6, line 55V` read cellulosic Signed and sealed this 10th day of April 1962m (SEAL) Attest: i,

fr# ERNEST W. sWIDER DAVID L. LADD Attesting Officer Commissioner of Patents 

11. CATAMENIAL TAMPON COMPRISING AN ELONGATED MASS OF ABSORBENT MATERIAL ADAPTED TO BE CARRIED IN THE VAGINA OF A WOMAN DURING PERIODS OF MENSTRUAL DISCHARGE AND MEANS ATTACHED TO SAID MASS OF ABSORBENT MATERIAL FOR REMOVING SAID MASS FROM THE VAGINA, SAID ABSORBENT MATERIAL CONTAINING AS AN ESSENTIAL INGREDIENT SODIUM CARBOXYMETHYLCELLOSE WHICH IS FIBROUS IN NATURE AND SUBSTANTIALLY INSOLUBLE IN WATER. 